Date Published: February 10, 2017
Author(s): Ying Chen, Sok Kean Khoo, Richard Leach, Kai Wang.
Extravillous trophoblast (EVT) invasion is required for remodeling uterine tertiary arteries and placenta development during pregnancy. Compromised EVT invasion may contribute to the pathology of placenta-related diseases. Metastasis -associated protein 3 (MTA3) is one of the subunits of nucleosome remodeling and deacetylation (NuRD) complex that represses transcription in a histone deacetylase-dependent manner. MTA3 is reported to be down-regulated in preeclamptic placentas, suggesting its potential role in EVT invasion. Here, we investigate the role of MTA3 in EVT invasion by studying its molecular mechanisms in EVT cells. First, we confirmed MTA3 expression in the EVT cells in human placenta using immunohistochemistry. We then used lentivirus-mediated MTA3 short hairpin RNA (shRNA) to knock down MTA3 expression in EVT-derived HTR8/SVneo cells and found higher invasion capacity in MTA3 knockdown cells. Using quantitative real-time PCR, we showed higher expression of invasion-related genes matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), and transcription factor Snail in MTA3 knockdown compared with control cells. Co-immunoprecipitation-Western blot assay showed the protein-protein interaction of histone deacetylase 1 (HDAC1), a subunit of NuRD, with MTA3 in HTR8/SVneo cells. Co-immunoprecipitation-Mass spectrometry assay further identified 71 proteins interacting with MTA3, including NuRD subunits, heterochromatin proteins, epigenetics modifiers and transcription factors. This result not only indicated the involvement of NuRD complex in MTA3’s function, but also demonstrated the complicated multiple co-players in MTA3 and NuRD complex mediated transcription repression in EVT. In summary, our data demonstrates that MTA3 regulates EVT invasion and related gene expression via NuRD complex in EVT.
Extravillous trophoblast (EVT) invasion is required for remodeling uterine tertiary arteries and placenta development [1,2]. Compromised EVT invasion is known to be related with the pathology of placenta-centered diseases such as preeclampsia and intrauterine growth restriction (IUGR) [3–5]. Invasion-related genes such as transcription factor Snail , matrix metalloproteinase 2 (MMP2)  and matrix metalloproteinase 9 (MMP9)  have been reported to play critical roles in EVT invasion and dysregulations of these genes may contribute to the etiology of preeclampsia and IUGR [9–11].
Dynamic reconstruction of epigenome happens in the trophoblast differentiation and function and chromatin remodeling proteins such as MTA3 are known to play important roles in this process . MTA3 is a subunit of NuRD complex and is involved in the regulation of villous trophoblast differentiation and fusion [15,16]. In this study, we showed inhibition of MTA3 correlates with increased trophoblast invasion and up-regulated invasion-related genes MMP2, MMP9, and Snail in EVT cells. In addition, 71 interacting proteins for MTA3 were identified. These proteins include NuRD subunits, heterochromatin proteins, epigenetics modifiers, and transcription factors.